Illustrating a huge weakness in border security, undercover federal agents drove into the United States from Canada and Mexico with enough radioactive material in their rented cars to build a pair of dirty bombs.

The good news is that the material, cesium-137, triggered the sophisticated radiation alarms in Texas and Washington state. The bad news is that U.S. customs agents were easily tricked with counterfeit Nuclear Regulatory Commission documents that that were copied from the internet and fake shipping documents from a fictitious company.

The undercover operation to test border security was conducted by the Government Accountability Office, the non-partisan investigative arm of Congress, and the frightening 12-page report can be viewed on its web site.

Among its findings is that customs agents are not able to check whether a person caught with radioactive matierals is in fact permitted to possess them under a government-issued license. In other words, nuclear smugglers with fake documents must raise suspicions in other ways to be stopped with their illegal cargo.

At least the radiation monitors actually work, but as one blogger writes; apparently that doesn’t matter because they could just as easily have gotten the material shipped to Washington D.C. since the undercover agents bought the radioactive material by phone from a commercial supplier.